- Geologic chance of success, or the inverse risk, is that element in the oil and gas industry, that defines the chance of making a discovery. As such, before discussing risks, and its association with the oil and gas exploration, we need to define what success, or the chance of making a discovery actually is. A discovery That definition seems fairly straight-forward, until you look a bit closer at the wording, and find the phrasing "significant quantities" of potentially moveable hydrocarbons. Minimum quantity of hydrocarbons found in, say, west Texas, where it is relatively cheap to economically drill and produce hydrocarbons. And thus, make discovery, would only categorize as a show and say, North Sea well. Where it's much more expensive to drill complete and produce hydrocarbons. Significant quantities relates to geology to economics, in the fact that the quantity discovered must be perceived as meeting an economic threshold. So, for a well to be geologically successful, it must meet criteria that is particular for its circumstance. We will now do a quick review of the geologic elements required for success. This is a very brief review. If you're interested in more in-depth discussion on each of these topics, there's a separate Knowledge Edge series that discusses each element in much greater detail. Generation. There must be a source where hydrocarbons have actually been generated. In brief, source rocks are formations that contain sufficient amount of TOC, or total organic carbon. It has matured to the point that hydrocarbons have both been generated and expelled. Migration. There must be a migration pathway through which hydrocarbons generated in the source rock interval can move, or migrate from that source rock interval into the sedimentary interval acting as the reservoir. Reservoir. There must be a reservoir section which is a sedimentary interval, where hydrocarbons generated in the source rock can be stored. A reservoir is a formation that has sufficient porosity and permeability, such that the hydrocarbons can first be stored in significant quantities, and then produced at a sufficient rates, that one or more wells can produce significant quantities of the hydrocarbons at a sufficient rate to constitute a discovery. As stated in previous bullet, reservoir formations are geologic formations with significant permeability. In other words, they have properties that allow oil or gas to flow through that formation with relative ease. As this is the case, reservoir intervals must be in a subsurface configuration, such that hydrocarbons that have been generated from the source and then migrated into the reservoir are now trapped in that formation. These traps take varying forms. From subsurface structures, such as anticlines, which tilt to fault blocks. To stratigraphic traps, formed by lateral variations in the types of sediments that were formed. Timing. As you can imagine, all of these elements must take place in specific order. Hydrocarbons generated in the source rock must migrate into the reservoir rock at such a time as the trap has already been formed. Finally, you might wonder if these elements are weighed in some relative level of importance. And the answer is no. Each of the five elements mentioned above must take place in order, to have geologic successful hydrocarbon discovery. Should any of these five not be in place in the proper order, discovery will not take place. This final slide is a hypothetical model for a successful project. Note the time is denoted on the horizontal axis, and starts about 130 million years ago, during the Cretaceous. Vertical axis marks major changes in geology, or geologic events. These events are primarily depositional, and take place due to variations in sea level. There is one structural event that takes place in our hypothetical area. First event is deposition of an organic-rich marine shale. This marine interval is followed by the deposition of a more sand-rich deltaic sequence that would serve as a reservoir. Next, the reservoir is vertically sealed by deposition of more shale-rich deltaic sequence. After which, faulting occurs which juxtaposes the shale-rich sealing interval with reservoir interval, that's providing a lateral seal. Finally, we have the source fault interval, reaching time, temperature, and pressure levels, that transform the organic marine sediments, first into carrigan, and then, into oil and/or gas. Note that all factors previously mentioned in this presentation are in place and in the proper order. Thus, making it our hypothetical example a successful product.